For Professional/monthly plans, all of your billing information - including the ability to add/update billing details and to download all historical invoices - can be accessed via your Billing page. 

Your Billing page can be accessed, by account architects, by clicking on "Settings" in the navigation bar and then "Billing". 

For all other paid plans, invoices are emailed to you directly from our accounts team. Please contact them to discuss any billing related matters.